Document Detail


Development of squeeze flow in mechanical heart valve: a particle image velocimetry investigation.
MedLine Citation:
PMID:  16883118     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Fluid between the reducing flow channel of the valve occluder and the orifice wall tends to be squeezed out of the flow channel, causing a high-speed flow. The squeeze flow is accompanied by a sharp local pressure drop, which may result in potential cavitation phenomenon in a mechanical heart valve (MHV). Limited experimental investigation has been conducted into the flow physics of this squeeze flow phenomenon, which is likely to be the origin of MHV cavitation. We used a pulsatile test loop simulating physiologic flow conditions and an actual-size transparent MHV model for flow visualization. A digital particle image velocimetry (DPIV) system incorporated with a microscope was applied to observe flow within a narrowing channel. A triggering mechanism was designed so that the DPIV system could be timed to capture images when the valve occluder was near its closing position. A series of images within the channel from 1.4 to 0.1 mm were captured. As the gap between the tip of the valve occluder and orifice wall becomes narrower, evidence of high-speed jet flow becomes more apparent. When the flow channel is reduced to around 0.1 mm, flow velocity of up to 2 m/s was noted. A sudden increase in high-speed jet flow causes a corresponding reduction in local pressure, and is a likely source for potential cavitation.
Authors:
Pei Zhang; Joon Hock Yeo; N H C Hwang
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  ASAIO journal (American Society for Artificial Internal Organs : 1992)     Volume:  52     ISSN:  1058-2916     ISO Abbreviation:  ASAIO J.     Publication Date:    2006 Jul-Aug
Date Detail:
Created Date:  2006-08-02     Completed Date:  2006-09-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9204109     Medline TA:  ASAIO J     Country:  United States    
Other Details:
Languages:  eng     Pagination:  391-7     Citation Subset:  IM    
Affiliation:
School of Mechanical & Automation Engineering, Shanghai Institute of Technology, Shanghai, China.
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MeSH Terms
Descriptor/Qualifier:
Blood Flow Velocity
Heart Valve Prosthesis*
Hemorheology*
Prosthesis Design
Pulsatile Flow

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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